Permission of senior customs commissioner replaces lower-officer sanction and fee requirement under amended Customs Act. The amendment substitutes the sanctioning clause in section 65 so that discretion is exercised 'With the permission of the Principal Commissioner of Customs or Commissioner of Customs and subject to such conditions,' replacing the prior requirement for sanction by Assistant or Deputy Commissioners and the explicit on-payment-of-fees provision, thereby reallocating decision-making authority to senior commissioners and removing the stated fee obligation while retaining conditional permission.